Hi, I hope I my understanding is sufficient. I am posting here just in case I am off the rails, which could well be the case. I want to set my bias on my mono blocks which have 3 tubes each. The output tube is a 45 tube. Some years ago, a friend made them for me. He planned to tweak them much more, but passed away before that could happen. I have listened to them for several years now, and absolutely love them.
I never knew what to set the bias to, and my friend was dead. Each mono-block has a bias pot. I recently bought a couple tubes that tested stronger and ended up messing with the bias again. I have ordered a bias tool from china that will allow me to plug the "tool" into my 45 tube socket and insert the two leads from it directly into my meter. While I wait for the tool to arrive, I want to make sure that I know what to do with it. I asked the seller, but he responded in Chinese.
I have looked up the Plate Current for several brands of 45 tubes and the three numbers that keep coming up are 31, 34 & 36. So, my question is, do I just want to have say 34mA come up on my meter, which is the middle number for plate current? Or, is it more complicated?
If having 34mA come up on my meter gets me into the ball park, I plan to do the following.
Set meter to milliamps
insert tool into socket, and tube into tool
attach leads appropriate for measuring current
adjust bias pot to lowest bias
turn amp on, and let it warm up good
slowly turn bias pot up until reaching 34mA
Please tell me if I have any part of this wrong. Please help me get the best sound I can out of this amp WITHOUT killing tubes which I can not afford to replace very often.
Sincerely,
Benjamin Webber